Strong impact of lattice vibrations on electronic and magnetic properties of paramagnetic Fe revealed by disordered local moments molecular dynamics
2016 (English)In: PHYSICAL REVIEW B, ISSN 2469-9950, Vol. 93, no 22, 224411Article in journal (Refereed) PublishedText
We study the impact of lattice vibrations on magnetic and electronic properties of paramagnetic bcc and fcc iron at finite temperature, employing the disordered local moments molecular dynamics (DLM-MD) method. Vibrations strongly affect the distribution of local magnetic moments at finite temperature, which in turn correlates with the local atomic volumes. Without the explicit consideration of atomic vibrations, the mean local magnetic moment and mean field derived magnetic entropy of paramagnetic bcc Fe are larger compared to paramagnetic fcc Fe, which would indicate that the magnetic contribution stabilizes the bcc phase at high temperatures. In the present study we show that this assumption is not valid when the coupling between vibrations and magnetism is taken into account. At the gamma-delta transition temperature (1662 K), the lattice distortions cause very similar magnetic moments of both bcc and fcc structures and hence magnetic entropy contributions. This finding can be traced back to the electronic densities of states, which also become increasingly similar between bcc and fcc Fe with increasing temperature. Given the sensitive interplay of the different physical excitation mechanisms, our results illustrate the need for an explicit consideration of vibrational disorder and its impact on electronic and magnetic properties to understand paramagnetic Fe. Furthermore, they suggest that at the gamma-delta transition temperature electronic and magnetic contributions to the Gibbs free energy are extremely similar in bcc and fcc Fe.
Place, publisher, year, edition, pages
AMER PHYSICAL SOC , 2016. Vol. 93, no 22, 224411
Condensed Matter Physics
IdentifiersURN: urn:nbn:se:liu:diva-130063DOI: 10.1103/PhysRevB.93.224411ISI: 000377497800002OAI: oai:DiVA.org:liu-130063DiVA: diva2:947016
Funding Agencies|Swedish Research Council (VR) [621-2011-4417, 330-2014-6336, 2015-04391]; Marie Sklodowska Curie Actions [INCA 600398]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFOMatLiU) [2009 00971]; Deutsche Forschungsgemeinschaft (DFG) [KO 5080/1-1]; European Research Council (ERC) under the European Union (EU) Seventh Framework Programme (FP7)/ERC ; ERC under the EUs Horizon Research and Innovation Programme ; Swedish Foundation for Strategic Research (SSF) program SRL Grant [10-0026]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009 00971]; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005, RFMEFI58715X0023]2016-07-062016-07-062016-07-27